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*Criteria

Purpose

To specify certain criteria that need to be satisfied in a static analysis, and to define how the model is to be adjusted to satisfy the desired criteria.

Theory

Refer to Solution Criteria Automation for further information on this feature.

Keyword Format

The keyword begins with a mandatory line defining the adjustment criterion, which may be repeated as often as necessary for multiple criteria:

CRITERION=Criterion Type, MONITOR=Criterion Monitor, TARGET=Target Value [, TOLERANCE=Target Tolerance]

Criterion Type may be HANGOFF ANGLE, TENSION, AXIAL STRESS, AXIAL STRAIN, BENDING STRESS, BENDING STRAIN, BENDING MOMENT, SUPPORT REACTION, SEABED CONTACT or VON MISES STRESS.

Criterion Monitor refers to an element number, an element label, an element set or a guide name definition. Target Value is a numerical value of the Criterion Type you want to achieve. Target Tolerance (optional) is a percentage that is permitted as an acceptable deviation from the target value and defaults to 1% if not specified.

The second line of the keyword is mandatory line specifying the adjustment variable. The adjustment variable options are NODE, VESSEL or LENGTH. The format of the line depends on the selected option.

Line specifying that a nodal location is to be varied (the direction of motion is controlled by the specified vector):

VARIABLE=NODE, ADJUST=Node (Number or Label), VECTOR=Vector Name

Or:

Line specifying that a vessel location is to be varied (the direction of motion is controlled by the specified vector):

VARIABLE=VESSEL, ADJUST=Vessel Name, VECTOR=Vector Name

Or:

Line specifying that a section length is to be varied:

OPTION=LENGTH, ADJUST=Element (Number or Label or Set Name)

 

Vector Name refers to a vector defined using *VECTOR.

Finally the last line of the keyword is optional, and contains some solution parameters:

[MAX ITERATIONS=Max Iterations][, MIN ADJUSTMENT=Min Adjustment][, MAX ADJUSTMENT=Max Adjustment] 

 

Max Iterations is the maximum number of iterations permitted to satisfy the criteria. This entry is optional and defaults to 100 if omitted. Min Increment is the lower bound that Flexcom may adjust the variable by in order to satisfy a criterion. This entry is optional and defaults to 0.1m (or 0.1 degrees for angular adjustments) if omitted. Max Increment is the upper bound that Flexcom may adjust the variable within a single increment. This entry is optional and defaults to 50m (or 10 degrees for angular adjustments) if omitted.

table input

Criterion Type

Criteria Variable – Adjust Node

Criteria Variable – Adjust Length

Criteria Variable – Adjust Vessel

Criteria Solution Parameters

Notes

(a) Note also that *PRINT is used to request additional printed output to the main output file. Specifically, the OUTPUT=CRITERIA option may be used to request additional information regarding solution convergence towards specified criteria.